This invention relates in general to delaying the opening of parachute canopies and in particular canopies of the ram air-inflated airfoil type.
The mechanical reefing of parachute canopies by sliders on the canopy suspension lines for the purpose of delaying canopy opening and/or reducing canopy opening shock is already well known as disclosed, for example, in U.S. Pat. Nos. 1,266,508, 2,566,585 and 2,754,074 to Ludtke, Smith and Schade, respectively. According to such prior art arrangements, opening of hemispherical canopies is physically restricted to a decreasing extent as the reefing sliders are displaced downwardly from an upper reefing position along converging suspension lines under canopy opening forces. Such descent of the slider reefing device is aerodynamically retarded according to the Smith and Schade patents. The use of such a conventional slider reefing device for a ram-air inflated airfoil canopy of a glide parachute was more recently shown in U.S. Pat. No. 4,540,145 to Matsuo. Further, according to the Matsuo patent inflation, of the cells separating the upper and lower airfoil surfaces of the canopy is additionally restricted by mechanically closing of the otherwise open leading edge portion of the canopy through which the inflow of air enters the cells. The reefing system disclosed in the Matsuo patent therefore involves a rather extensive arrangement of canopy attached guide rings and reefing lines to which the slider is connected and a staged line cutting operation which is of costly installation and readily subject to malfunction.
It is therefore an important object of the present invention to provide a less costly yet automatically operative system for delaying the opening of forward gliding parachute canopies of the ram air inflated airfoil type. An additional object is to provide such a system which is both reliable and effective to modulate the canopy inflation and opening process during deployment of the parachute.